I've discovered that I can pop my shoulder out backwards whenever I want to. It doesn't pop out on its own, just when I do it. Should I have surgery to tighten it up?
You are describing what sounds like a posterior shoulder instability. If it dislocates more than once, it's called a recurrent instability. If you can pop it in and out yourself, it's a voluntary instability.

Treatment for voluntary shoulder instability, especially in the posterior direction is a highly debated topic. Surgery isn't usually recommended for voluntary shoulder instability. The recurrence rate after soft tissue repair is too high (as much as 72 per cent).

Conservative care may be a better approach to this problem. Physical therapy is advised to help you strengthen the muscles around the joint. Biofeedback is often used to help retrain the muscles in addition to strengthening them. They must learn when and how to contract and with the right amount of force for the action.

Activity modification is another big part of nonsurgical repair for voluntary recurrent shoulder dislocation. The first step is to avoid dislocating the joint. The therapist will tell you if there are other motions to avoid during the rehab process.